Fabrication of S-scheme hollow TiO2@Bi2MoO6 composite for efficiently photocatalytic CO2 reduction

Herein, an S-scheme hollow TiO₂@Bi₂MoO₆ heterojunction was synthesized for photocatalytic reduction of CO₂ under simulated sunlight. Among all prepared composites, the TiO₂@Bi₂MoO₆ with 20% of TiO₂ exhibited the highest CO yield (183.97 μmol/g within 6 h), which was 4.0 and 2.4 times higher than pristine TiO₂ and Bi₂MoO₆, respectively. The improved photocatalytic activity may be due to the formation of S-scheme heterojunction to promote the separation and transfer of photogenerated charge carriers. Additionally, this hollow structure provided abundant sites in terms of CO₂ adsorption and activation. Meanwhile, the photogenerated charge transfer mechanism of the S-scheme was verified by work function calculations, Electron paramagnetic resonance (EPR) measurements as well as X-ray photoelectron spectroscopy (XPS). This research presents a novel approach to improve photocatalytic reduction of CO₂ via morphology modulation and the fabrication of S-scheme heterojunction.